A sputtering process denotes a technique in which high-speed argon ions collide with a target to eject target atoms and the ejected target atoms are then supplied to a substrate to form a thin film on a surface of the substrate. The sputtering process is not only being used in a semiconductor fabrication process and fabrication of micro devices such as microelectromechanical systems (MEMS), but is also being used in coating for improving abrasion resistance of various tools, dies, and automotive parts.
In a case where a nanocomposite thin film including an amorphous thin film or amorphous phase is fabricated by sputtering, a target formed of an amorphous material may be used. The amorphous target may be formed of a multi-component alloy having high glass-forming ability, and heterogeneous metal elements ejected from the amorphous target may form an alloy thin film having an amorphous phase on the surface of the substrate.
However, a temperature of the amorphous target may be increased due to the collision of ions during a sputtering process, and a structure near the surface of the target may be changed due to the increase in temperature. That is, localized crystallization may proceed on the surface of the target due to characteristics of the thermally unstable amorphous phase when the temperature of the target increases. Such localized crystallization may cause structural relaxation and volume changes in the target. As a result, brittleness of the target may increase and thus, the target may be easily fractured during the sputtering process. In a case where the target is fractured during the process, serious limitations in production may occur. Therefore, it is very important to secure a stable target in which such fracture does not occur during the sputtering process.